Prepare and sauté the duck breasts as described in Steps 1 and 2 in the Master Recipe for Pan-Sautéed Moulard Duck Breast on page 177. Remove to a carving board, and let rest at least 10 minutes.

Meanwhile, add the shallots and duck fat to the skillet and cook over moderately low heat, stirring, until softened, about 2 minutes. Add the wine and herbs to the skillet and boil until reduced by half. Stir in the mustard and heavy cream. Adjust the seasoning. Thinly slice the meat crosswise on the diagonal and arrange overlapping on a serving platter. Spoon the sauce over the slices and serve at once.